For architects, says Narinder Sagoo, Head of Design Communications at Foster + Partners, drawings are about story telling. They are also a highly effective way of raising questions about design projects. Although the history of architecture—certainly since the Italian Renaissance—has been mapped by compelling drawings asserting the primacy, and reflecting the glory, of fully resolved buildings, there is another strain of visualisation that has allowed architects to think through projects free of preconceptions.

Such drawings are largely the child of the architecture of recent decades when the form, plans, and sections of particular buildings have been allowed to evolve independently of specific canons of design. Norman Foster, an architect who fills sketchbook after sketchbook with pencil drawings, has used these to think through the essential nature of design commissions. The immediacy of his inexhaustible sketching has led him to evolve radical alternatives for building types that, at one stage or another in their evolution, appeared to have got stuck in a less than satisfactory groove.

Narinder Sagoo, for whom drawing is second nature, delights in one particular drawing Norman Foster made while thinking through design proposals for Stansted Airport [above]. It depicts a hand turning the building upside down. This direct and almost cartoon-like drawing might seem very simple, yet it represents the moment when Foster determined to move the machinery of an airport terminal from its heavily laden roof and putting it underground. Now, the roof could be no more and no less than a lofty and airy umbrella or parasol, light, effortless and a world removed from the claustrophobic low and false-ceilinged airport horrors of the 1960s through to the late 1980s.

What Foster, Sagoo and their colleagues have discovered time and again and around the world is that clients like these interrogative and narrative drawings more than the architects themselves might once have thought possible. Until recently, most architects tended to use client drawings assertively. These might show highly polished renderings of finished schemes at a stage when the client might not be exactly sure of quite what the building they were in the process of commissioning might, could or should be.

“While creating drawings that question the brief and preconceptions of all concerned”, says Sagoo, “the most important 'chess move' is putting yourself alongside the client and user, rather than opposite. Drawing, after all, is a language and every language requires two sides to function successfully. So, through drawing we can arrive at conclusions together... check mate!”

Now, Sagoo sketches with Apple Pencils on the screens of iPads. This technology allows him to draw at speed while employing a wide range of techniques. Most importantly, it allows him to show clients drawings as they emerge so that the design thinking, and questioning, through a project is very much alive in front of their eyes. So, here is the architect drawing, as architects always have, but with the assistance of a technology that brings drawing alive in a cinematic way.

So, for Sagoo, a judge of the 2017 Architecture Drawing Prize, winning entries will not have to be highly composed (although, of course, they could be). They might be drawings that show how architects question projects and how a drawing, perhaps very different indeed from that evoking some noble Beaux-Arts façade, might just change the very nature of buildings.

This short essay, written by the author and critic Jonathan Glancey, coincides with the launch of the inaugural Architecture Drawing Prize - a competition curated by the World Architecture Festival, the Sir John Soane's Museum, and Make. The deadline for the award is the 18th September 2017 and successful entries will be exhibited in both London and Berlin.